CHAPTER 3 - Foundations of RF & Microwave Circuit Characterisation
130
Therefore we may write
If we ignore losses in eq. (3.2-4), we can rewrite the reflection coefficient for
=25Ω as
( )
Comparing eq. (3.2-11) and (3.2-7), we can see that although the magnitude of is identical for both
terminations, when
=25Ω the phase of the reflection coefficient is rotated clockwise by an extra
rad or 180ιǤ If we examine the simulation results for when
=25Ω with those obtained when
=100Ω, we can clearly see this. Compare Figure 3.2-2 and Figure 3.2-8, Figure 3.2-3 and Figure
3.2-9, Figure 3.2-5 and Figure 3.2-10, Figure 3.2-7 and Figure 3.2-11 and you will notice this 180ι
phase shift.
Figure 3.2-8 Reflection coefficient when transmission line's physical length , electrical length =0ι ιǡ =25Ω
0
15
30
45
60
75
90
105
120
135
150
165
-180
-165
-150
-135
-120
-105
-90
-75
-60
-45
-30
-15
Graph 1
Swp Max
1000 MHz
Swp Min
1000 MHz
Mag Max
1
0.2
Per Div
1000 MHz
Mag 0.3333
Ang 180 Deg
S(1,1)
Schematic 1
(3.2-10)
(3.2-11)
Conquer Radio Frequency
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